Process for the production of cellulosic textile fabric



Patented Aug. 15, 1939.

UNITED STATE-S.

PROCESS FOR THE PRODUCTION OF CELLU- LOSIC TEXTILE FABRIC Donald H. Powers, Moorestown, N. J and Onslow B. Hager, Philadelphia, Pa., assignors to Riihm & Haas Company, Philadelphia, Pa.

No Drawing. Application May 1, 1937, Serial No. 140,170

6 Claims. (or. 91-10) ings which are resistant to creasing and crushing but thus far no really satisfactory fabric 10 has been obtained. Cotton and other cellulosic fabrics have been treated with various other materials, notably solutions of cellulose in aqueous solutions of quaternary ammonium bases, for the g titles of resin than ordinary, cellulose, there is 'a purpose ofproducing"affaFiic siinilar todinen.

15 They have also been treated with resins such as phenol-formaldehyde and urea-formaldehyde resins for thepurpose' of increasing their resistance 'to creasing.

We have now found that a fabric having the 20 crush resistance and feel of wool combined with the absorbent power and coolness of linen can be obtained-by treating a cotton fabric, which has been coated with cellulose, with a urea-formaldehyde resin in such manner that the resin 25 penetrates both the fiber and cellulose coating.

In this manner a suiting material can be made from cotton'which has all the advantages of linen suitings andfat" the same time possesses the crush resistance and feel .of wool. Thus, the

80 cellulose coating imparts a finish and sheerness it too canabsorb the. urea-formaldehyde solu-- tion. In this way each individual fiber of the original fabric after cellulose coating can. ab-

sorb more urea-formaldehyde resin without hav- 45 ing any substantial amount of it on the surface which would tend to bindboth fibers and threads together thus yielding a harsh, stiff fabric. This hardness is undesirable in suiting material. I

We have found, furthermore,'that very light 50 weight, cotton fabrics, such as organdies and lawns, can be rendered quite sheer and perma;

nently crisp by first applying the 'cellulosic coating in the prescribed manner and then introducing into the thus coated fabrics a remarkablede- 55 gree of resilience and resistance to creasing by cent. in weight.

impregnating with the urea-formaldehyde resin. The crush resistance thus obtained is much greater than is obtained from an equivalent amount of resin applied to the fabric which has not been previously coated with cellulosic materials.

The fabric is usually so treated with the cellu lose solution that it increases about five per As the specific gravity of the cellulose coating and that of .the original cotton fiber are about the same,this means an increase of flvepercent. in the volume of each fiber and, since regenerated celluloses absorb greater quanconsequent increase of about eight per cent. in the amount of urea-formaldehyde resin which it can absorb and retain within itself. On ac-. count of this increase in the volume of each fiber and more, particularly because of the greater concentration of resin in a layer farther removed from the axis of the fiber resulting in greater resistance to bending according to well known mechanical principles, the improvement'in the crush resistance of the finished fabric is much greater than that obtained by treating the orig+ inal cotton with urea-formaldehyde resins only.

A cotton fabric treated with urea-formaldehyde resin and subsequently coated with cellulosic materials is inferior to that obtained as described above, and is of much less value as a suiting material or dress fabric although distinctlysuperior to the original fabric having no chemical finish of any kind. When the fabric is first treated with resin and after treated with cellulose, the high-alkalinity of the cellulose coating solution removes an appreciable portioirof the resin and deposits on the surface of the fiber a film which does not impart as desirable a crush resistance as is obtained by the herein de-' scribed process. Consequently, by first treating 40 a fabric with a cellulose solution, removing the last traces of alkali frcm this coating solution, and then treating with the resin, an unusually attractive fabric is produced which is substantially non-shrinkable and non-crushing. H

The new treatment; which consists in firs applying the cellulose coating to the fibers and then impregnating them with urea-formaldehyde resin, yields a fabric which is far superior to the original fabric or to any obtained by the 'individual treatments. I Cellulosic yams mayalso be improved by the same .treatment, viz: First coating them with H cellulose and. then impregnating them with a.

urea-formaldehyde condensation product which greater resistance to creasing than fabrics woven from the untreated yarns.

The cellulose coating may be pure cellulose as precipitated from a viscose or cuprammonium solution but we prefer touse solutions of cellulose in quaternary ammonium bases, particularly those which have'a benzyl group such as trimethyl benzyl ammonium hydroxide and other similar bases described in U. S. Patent No. 2,009,- 015, granted July 23, 1935. The coating may also be a cellulose ether-such as hydroxyethyl cellulose, methyl cellulose, etc., but only those ethers are applicable which after application form coatings that are permeable to aqueous solutions, particularly to' those of the urea-formaldehyde resin or the ingredients from'which it is made.

In general the fibers are coated with cellulose by passing the fabric through a solution thereof in a quaternary ammonium base such as trimethyl benzyl ammonium hydroxide containing about four to eight per cent. of cellulose and squeezing it under such conditions that the fabric takes up about its own weight of solution. It is then dried to touch and run into aprecipitating' bath such as dilute acid, washed thoroughly and dried. When thoroughly dry, it is run through the impregnating solution which is usually a solution of dimethylol urea of twenty to thirty per cent. concentration or one containingthe equivalent amountsof urea and formaldehyde and again squeezed so that it picks up about its own weight of the solution. Eollowingthis the fabric is'dried and the resin cured by heating it for a short period of time at temperatures ranging from about 275 to 350 F. 40

and more absorbent. When made up into clothing, it gives a garment which on account of its Fabric treated in this way is much firmer; fuller coolness is very suitable for. use in hot weather. It is also much more resistant to crushing than an untreated fabric.

The following examples are given by way of illustration but the invention is not limited'to theexact details of time, temperature, concentration, etc., shown as it may otherwise be practiced'withIn the scope of the appended claims.

4 Example 1 A 40'}: 32 cotton O'snaburgis desizeifand run through a cellulose solution which contains about six per cent. cellulose. This solution is prepared by adding sufllcientv five per cent. caustic soda solution to a fifteen per cent. solution of cellulose in concentrated trimethyl benzyl ammonium hydroxide to dilute it to six per cent. cellulose content. After passing through this solutiofi, the fabric is squeezed so that the amount of solution it has absorbed is ninety-to one hundred per cent. of the dry weight of the fabric. Itis then dried until it is dry to touch and run through a two per cent. sulfuric 'acid solution to precipitate the cellulose'on the fiber following which it is washed, dried and passed through the impreg-' nating solution. This solution contains thirty per cent. of dimgthylol urea, one per cent. of di-,

ammoniumphosphate as a catalyst for the resinification of the diinethyiol urea and 0.3 per cent. of 'dimethyl lauryl benzyl ammonium chlo-' ride as a wetting agent. After passing ,through thissolution the fabric is again dried and the resin with which it has been impregnated is cured.

by heating at 290 F. for ten minutes. The resulting material is soft and resilient and will retain its weight and appearance even after repeated washings. The individual fibers have a five per cent. greater diameter and the entirefabric is about twenty-five per cent. heavier. Its tensile strength has also been increased by about twenty per cent.

' Example 2 own weight of solution, dried, slightly acidified with weak sulfuric acid, rinsed and dried. This fabric is then run througha solution prepared by mixing one part of urea with two parts of forty per cent. formaldehyde solution. This mixture is made slightly alkaline with hexylmethyleney tetramine, boiled for three minutes, cooled and diluted with water so that the resulting solution contains twenty-five per cent. of resin. Before applying this solution to the fabric one-half per cent. of acetic acid is added. The fabric coated with the hydroxy ethyl cellulose is passed through this bath, hydro extracted and cured for ten minutes at 3.40 F., rinsed and. dried.

In this manner an absorbent, crush-resistant suiting material is obtained.

Example 3 Aa136x 96 co tton shirting material is run through a cuprammonium soluti'ohrontainihg four per cent. of dissolved cellulose and squeezedso that it takes up approximately its own weight of solution. The cellulose is then precipitated by passing the fabric through a sodium sulfite solution and subsequently rinsing it with weak sulfuric acid, washed and dried. The fabric thus coated is "run through a solution containing twenty per cent. 'of dimethylol urea and one per cent. of ammonium acetate. After squeezing so that the fabric takes up about its own weight of the solution, it is dried and heated forten minutes at 290 F. to harden the'resin. The resulting fabric makes a very attractive ladies dress'material having the properties of linen and resistance to mussing and crushing of wool.

Example! cent. solution of viscose, dried and passed into a precipitating bath containingtwo per cent. of sulfuric acidand two per cent. of sodium sulfate.- Itis then thoroughly rinsed, dried and passed through asolution containing thirty per cent. of dim'ethylol urea, one per cent. of acetic acid and A 36 x 26 sheeting is run through a five per one-half per cent. of. dimethyl cetyl butyl ammoniuin chloride. The fabric is then dried and heated to 300 F. for ten ininutestoharden the resin.

D Example 5' I I A 'Iii x'72 -lawn is passed through a four per cent. solution of cellulose in concentrated trimethyl benzyl ammonium hydroxide; squeezed 'free of. excess liquid so as to retain approximate-- ly its own weight of solution, and dried. by passing throughahot-tenter frame. The dried fab-' acid solution to'precipitate the cellulose and neutralize the excess alkalinity, squeezed. and

, 'ric is then run through a two per cent. sulfuric washed free of acid, dried and then run through a thirty per cent. solution of dimethylol urea containing four per cent. diammonium phosphate (based on the dimethylol urea). The fabric was squeezed so asto allow an equal weight of liquid to be taken up, dried and the resin then cured by subjecting the fabric to 270 to 280 F. for four minutes. The resulting material is stifi, wiry and sheer with an unusual degree of resilience considering its stiffness. The tensile strength is increased by about twenty per cent. and the fibers are so set that shrinkage is reduced. The resulting finish is a greatly improved, stiff organdy finish.

-In the foregoing examples cotton fabrics have been used for purposes otillustration but it is obvious to any one skilled in the art that linen, rayon, or combinations of these materials with each other or, with cotton can be treated in a similar way. While cellulose solutions are particularly suited for this work, it is obvious that alkali-soluble cellulose ethers are also suitable as they coat the fiber with an adsorbent film.

pregnating the coated fibers with an aqueous solution of a hardenabie urea-formaldehyde product, drying and heating to harden the ureaformaldehyde product.

2. The process of improving cellulosic fabrics and yarn which comprises applying to the fibers thereof a coating of cellulose, impregnating the coated fibers with an aqueous solution of a hardenable urea-formaldehyde product, drying and heating to harden product.

3. The process of improving cellulosic fabrics and yarn which comprises applying tothe fibers thereof a coating of an alkali-soluble-cellulose ether, impregnating the coated fibers with an aqueous solution of a hardenable urea-formaldehyde product, drying and heating to harden the urea-formaldehyde product.

4. The process of improving cellulosic fabrics and yarn which comprises passing them through a solution of cellulose in a quaternary ammonium hydroxide, drying and setting the cellulose on the fibers by treatment with dilute acid, rinsing, drying, impregnating with an aqueous solution of dimethylol urea, drying and heating to convert the dimethyiol urea to an insoluble resin.

5. A cellulosic fabric, the fibers of which carry a coating of cellulose, both fiber and coating being impregnated with a urea-formaldehyde condensation product.

6. A cellulosic yarn, the fibers of which have been coated with cellulose and subsequently imthe ureaformaldehyde pregnated with a urea-formaldehyde condensation product.

DONALD H. POWERS. ONSLOW B. HAGER. 

